1. Field of the Invention
The present invention relates to an electronic device, such as a mobile phone, having a display for showing a user""s private messages, and more particularly to a protective lens of the display for preventing light from the messages from being emitted outside of a predetermined central arc, thereby preventing the messages shown in the display from being observed by other people.
2. The Related Art
An electronic device, such as a mobile phone or a pager, usually has a display for showing text or image messages. The messages are displayed using a light source built into the electronic device. The display is covered by a lens for protection. A conventional lens is a transparent member allowing a user to read messages. The lens may also be formed with laser images to improve the visual effect, such as that disclosed in Taiwan patent application No. 87220130.
With the growing demand for personal privacy, it is becoming more desirable to have a lens that prevents people from seeing messages shown on a display except from a relatively narrow arc from which the user views the message. FIGS. 1 and 2 of the attached drawings disclose one such known lens 90. The lens 90 includes a flat, transparent glass plate 92 and a filtering film 94 adhering to an inner surface of the glass plate 92. The filtering film 94 is printed with a series of equally-spaced ink stripes 98 to block light from being transmitted through the lens 90 except in a narrow central arc, as is illustrated in FIG. 1. Thus a message shown on the display can not be seen from the sides outside of this arc.
A method of manufacturing the lens 90 will be explained with reference to FIG. 2. The method comprises the following steps: (1) directly printing ink stripes 98 on a film substrate 96; (2) cutting the film substrate 96 to form the filtering film 94; and (3) attaching the filtering film 94 to the glass plate 92.
However, this direct printing method is only adapted to a flat lens, because the ink stripes 98 are distributed in an equally spaced fashion.
The equally spaced distribution of ink stripes, however, is not suitable for a curved or arcuate lens because the distribution of distances between ink stripes must change for different locations on the arc of the lens to block light outside the same viewing arc as used with the flat lens.
Therefore, an object of the present invention is to provide a curved protective lens for a display which allows a user to readily read messages on the display while effectively preventing others from observing the messages.
Another object of the present invention is to provide a method for mass-producing display protective lens having different non-flat configurations.
These and other objects are achieved by a protective lens in accordance with the present invention. The protective lens includes a transparent glass substrate and a filtering film attached to an inner surface of the glass substrate. A plurality of parallel ink stripes are formed on a surface of the film and are distributed symmetrically from a middle to opposite sides according to a predetermined pattern. A method for manufacturing the protective lens is also disclosed. The method includes the steps of: (1) providing a mold having a plurality of recesses formed by etching a surface of the mold; (2) filling the recesses of the mold with ink; (3) pressing an elastically deformable body against the mold, thereby attaching the ink in the recesses to the elastically deformable body; (4) pressing the elastically deformable body against a membrane, thereby transferring the ink to the membrane, thus forming a filtering film; (5) attaching the filtering film to a surface of the glass substrate.
These and additional objects, features and advantages of the present invention will become apparent after reading the following detailed description of a preferred embodiment of the invention taken in conjunction with the appended drawings.